Monday, 19 April 2010

All eyes on TD-LTE in India and China


The TD-SCDMA and Long Term Evolution (TD-LTE) network will be massively deployed in China, the world's largest telecommunications country by number of telecoms users, in 2010, globally premier international market research and consulting firm Infonetics Research said in a forecast report.
More and more mobile carriers have started developing the LTE, including Verizon Communications Inc., China Mobile Ltd., and China Telecom Corporation Ltd., Infonetics noted. There will be no more than twenty LTE networks in the world at the end of 2010.

China Mobile Communications, the largest mobile telecom carrier in China, will establish three experimental TD-LTE (time division-long term evolution) networks separately in three coastal cities - Qingdao, Xiamen and Zhuhai - beginning the third quarter of 2010, according to the China-based China Business News Daily.

China's Ministry of Industry and Information Technology (MIIT), the carrier, handset and component makers, and handset solution suppliers in China in late 2008 began to cooperate for the development of TD-LTE in three phases, the report said.

The first-phase trial of technological concepts completed in June 2009, and the ongoing R&D and experiments in the second phase will be finished at the end of June 2010, the report indicated, adding the third phase will begin with China Mobile setting up three trial networks in the third quarter.

China Mobile Communications, the largest mobile telecom carrier in China, on April 15 inaugurated its first experimental TD-LTE network at the site of the 2010 Shanghai World Expo.

The trial network consists of 17 outdoor TD-LTE base stations made by Huawei Technologies completely covering the 5.28km square site and will be used to provide mobile high-definition multimedia services.

ZTE and Datang Mobile Communications Equipment as well as Motorola and Alcatel-Lucent have also set up TD-LTE access points inside a number of pavilions.

Motorola, Inc.'s Networks business has already announced in February that it has successfully deployed a TD-LTE network at the Expo Center for World Expo 2010 Shanghai China, and completed the first indoor over-the-air (OTA) TD-LTE data sessions at the site. These advancements demonstrate another milestone of collaborative industry efforts on TD-LTE commercialization, reaffirming Motorola's commitment to address the future needs of TDD spectrum operators in China and around the world.

These milestones follow the announcement by China Mobile Communications Corporation (CMCC) in 2009, that Motorola was selected as main equipment supplier to provide indoor TD-LTE coverage for pavilions at Shanghai Expo. During the Shanghai Expo, Motorola will provide an advanced end-to-end TD-LTE solution and the world's first TD-LTE USB dongles. Motorola will also leverage its orthogonal frequency division multiplexing (OFDM) expertise with professional services to deploy, maintain and optimize these leading-edge networks. Visitors will be able to experience applications such as high-definition video on demand, remote monitoring and high-speed Internet access services.

Motorola, Inc.'s Networks business announced on April 16th that it showcased an end-to-end TD-LTE demonstration via the world's first TD-LTE USB dongle at the Shanghai Expo site to support the "TD-LTE Showcase Network Opening Ceremony" hosted in Shanghai on April 15. Delegates at the ceremony experienced applications that run over a TD-LTE network via USB dongles, including high-definition video wall (simultaneous 24 video streams), remote monitoring and high-speed Internet browsing applications. This latest advancement demonstrates a major milestone of the collaborative industry efforts in building a healthy TD-LTE device ecosystem, reaffirming Motorola's commitment to TDD spectrum operators around the world.

Motorola, a leading provider of TD-LTE technology, and China Mobile share the same commitment to accelerating TD-LTE commercialization and globalization. "We are very excited to support China Mobile in bringing the world's first TD-LTE USB dongle demonstration enabled by our TD-LTE system," said Dr. Mohammad Akhtar, corporate vice president and general manager, Motorola Networks business in Asia Pacific. "A healthy devices ecosystem has always been critical to the development, commercialization and success of wireless network technologies. We are working closely with partners to drive this ecosystem as demonstrated by the advancement announced today. TD-LTE is now a commercial reality and we are very pleased to see that industry players are joining forces to accelerate TD-LTE globalization."

Interest in TD-LTE continues to grow because of several key factors: the low cost of TDD spectrum that is particularly attractive to emerging and developing markets; operators' continuing need for more capacity and spectrum; and the ability to hand-off between TD-LTE and LTE FDD networks. In effect, this ability to roam between LTE FDD and TD-LTE means operators can use TD-LTE networks to augment their FDD LTE network for more capacity or other applications such as video broadcasting, while operators choosing to use TD-LTE as their "main" network can still offer their subscribers the ability to roam to other operators' FDD LTE networks in different countries. Motorola is one of the few vendors in the industry that has expertise in, and is committed to investing in both FDD-LTE and TD-LTE, as well as WiMAX. By leveraging its orthogonal frequency division multiplexing (OFDM) expertise and WiMAX legacy, Motorola has built up its leadership position in TD-LTE with a number of industry-firsts.

Nokia Siemens Networks has inaugurated a TD-LTE Open Lab at its Chinese Hangzhou R&D facility. TD-LTE smartphone and terminal manufacturers will be able to use the lab to test the interoperability and functionality of their devices across TD-LTE networks.

"The development of terminals and devices has always been a bottleneck in the roll-out of new mobile technology," said Mr. Sha Yuejia, vice president of China Mobile. "We are thus more than happy to see that Nokia Siemens Networks has established a cutting-edge terminal testing environment, an initiative that we support wholeheartedly. After all, a healthy ecosystem needs efforts from all stakeholders."

Nokia Siemens Networks' Open Lab will provide an end-to-end testing environment for verifying the compatibility of terminals and devices with the company's TD-LTE network products and solutions. The lab will also provide consultancy and testing services to device manufacturers. Nokia Siemens Networks' TD-LTE R&D center in Hangzhou is fully integrated into the company's global network of LTE Centers of Competence.

Providing a live TD-LTE experience to operators in the region, Nokia Siemens Networks also recently kicked off a nationwide TD-LTE road show in China. Beginning in Beijing, the road show will cover more than ten provinces in three months, demonstrating the most advanced TD-LTE technology and applications.

In India, Even as the government hopes to raise around $9 billion from the 3G and BWA auctions, foreign telcos waiting in the wings are eager to unfurl a new technology — TD-LTE —which is akin to 4G technology.

US-based Qualcomm and Sweden's Ericcson aim to piggyback on TD-LTE, hoping that it will help them gain a toe-hold in India, the world's fastest growing mobile market. Qualcomm is to participate in the broadband wireless access (BWA) spectrum auction. If it does secure its bid in the auction, India could well become the first country after China to roll out TD-LTE.

TD-LTE, or Time Division Long Term Evolution, caters to peak download speeds of 100 Mbps on mobile phones, compared to the 20 Mbps for 3G and 40 Mbps for Wimax. LTE brings to the table additional spectrum, more capacity, lower cost, and is essential to take mobile broadband to the mass market.

The government has slotted the sale of two 2.3 GHz blocks of spectrum on April 11, providing 20 MHz spectrum in each of the country's 22 telecom circles. The base price has been set at $ 385 million. However, Qualcomm will need an Indian partner for its TD-LTE foray in the country since foreign direct investment is limited to 74%.

The US telco aims to use the 2.3 GHz spectrum band offered for TD-LTE-based BWA services. Sources in the know told TOI that the company would bid aggressively to corner one of the two BWA slots up for sale. There are 11 bidders for the BWA auction.

Asked to comment on the market dynamics, Sandeep Ladda, executive director, PricewaterhouseCoopers (PWC), said: "Though the Indian market is huge, it won't be smooth sailing post auction. We are adding 1 crore customers a month and in January, we added 1.9 crore customers, but the implementation of the new technology has its own cost. And India is a very cost conscious market."

Eager to play by the rules in India, Qualcomm has notified that it would enter into a joint venture with an Indian partner to launch its services and later exit from the joint venture after the network becomes operable.
Meanwhile, The WiMAX Forum has gone on the defensive during the WiMAX Forum Congress Asia in Taipei, Taiwan. The group is speeding up its time table to deliver the next generation of WiMAX--a reaction to heavy data use among WiMAX subscribers as well as the looming threat posed by Qualcomm and Ericsson's lobbying for TD-LTE in India.

Recently, the forum launched a global initiative to accelerate advanced WiMAX features that would double peak data rates and increase average and cell edge end user performance by 50 percent.

Mo Shakouri, vice president with the WiMAX Forum, said enhancements to the current generation of WiMAX weren't on the forum's roadmap, but were brought to the forefront at the urging of several WiMAX operators already facing capacity crunches. The forum reports that the average usage of data on WiMAX networks is close to 10 GB. Clearwire recently reported that mobile users average more than 7 GB of usage per month. In Russia, mobile WiMAX operator Yota sees more than 1 GB per month in data traffic from subscribers using its HTC smartphone. For laptops, it's 13 GB per month.

"Demand for data is moving so fast that we were pushed by many people to add this functionality," Shakouri said.

The WiMAX Forum has also been prodded to announce more detailed plans for 802.16m, and step up the timeline for its development via a new group called the WiMAX 2 Collaboration Initiative, which is made up of vendors Samsung, Alvarion, Motorola, ZTE, Sequans, Beceem, GCT Semiconductor and XRONet. The companies will work in tandem with the WiMAX Forum and WiMAX operators to accelerate the next-generation standard. WiMAX 2, the marketing name for the 802.16m standard, is expected to expand capacity to 300 Mbps peak rates via advances in antennas, channel stacking and frequency re-use.

The forum previously forecast 802.16m would hit in 2012 or 2013. But increasing demands for data--coupled with Qualcomm and Ericsson urging Indian mobile broadband license bidders to go with TD-LTE--motivated the forum to put some stakes in the ground and declare that WiMAX 2 equipment will meet certification by the end of 2011.

"There has been a lot of noise about TD-LTE, and the WiMAX Forum had not specifically given dates regarding timelines for 802.16m," Shakouri said. "Basically our announcement around 802.16m came about because of the noise in India."

The formation of the WiMAX 2 Collaboration Initiative is a marked change from the way the first generation of WiMAX was developed. Sprint Nextel was the entity driving the majority of the standards work as it was eager to get to market and begin building an ecosystem. Vendors are now taking the lead and driving equipment readiness before the 802.16m standard is finalized by the end of this year. Shakouri said the standard is 95 percent finished.

"Those companies are going to take a more active role inside the forum," Shakouri said. "They have all come together to speed up the process."

The group of vendors plans to collaborate on interoperability testing, performance benchmarking and application development before the WiMAX Forum establishes its certification program to narrow the gap between the finalized standard and commercial rollouts.
So how much of a threat is TD-LTE to WiMAX? Shakouri said the answer depends on spectrum decisions. "At this moment, the spectrum we are focusing on is separate, aside from what Qualcomm announced in India," Shakouri said. He also said that a TD-LTE ecosystem is at least two to three years behind WiMAX.

Many analysts speculate that TD-LTE will become the crossover technology that will prompt WiMAX operators to flip to LTE. Clearwire was part of a group of operators and vendors that last month asked the 3GPP standards body to begin working on specifications that would enable TD-LTE to be deployed in the 2.6 GHz band, which Clearwire uses for WiMAX. During the CTIA Wireless 2010 trade show last month, Clearwire CEO Bill Morrow reiterated the company's interest in deploying LTE when the technology catches up to WIMAX. He also called for one standard down the road.
Another initiative the forum is announcing this week is the launch of its Open Retail Initiative, a global program aimed at driving WiMAX into consumer devices sold directly or through retail channels that can be activated by the consumer over the air on the network. If you remember the evangelism of early WiMAX advocates like Barry West, this capability was supposed to be the Holy Grail of the technology.

Thursday, 15 April 2010

Femtocell Technology Map from Ubiquisys

Came across this very interesting Femtocell map from Ubiquisys.

The corresponding press release, titled "Ubiquisys Unveils Femto-Engine: the Complete Software Femtocell for Mobile Operators, Alongside an "Engine-Ready" Hardware Programme for OEMs" is available here.

Ubiquisys is also celebrating its sub $100 Femtocell. Press release here.

Wednesday, 14 April 2010

Pomegranate concept mobile: With video projector, live voice translator, harmonica, coffee maker, shaving razor, etc

The Pomegranate NS08 is a concept (fictional - though some people refer to it as a hoax) phone that promised amazing stuff until you dig deep and realise that its just an idea to market Communication Nova Scotia's Come to Life program. Check out the Youtube clip for the complete advertisement:


The following is from Wikipedia:

The Pomegranate phone is the latest campaign from Communications Nova Scotia's Come to Life initiative, the place-branding program of the Government of Nova Scotia. Communications Nova Scotia has been criticized by some for spending $300,000 on the ad campaign, though the website received more than 1,100,000 visits from 201 countries/territories since its launch on September 30, 2008, and they are considering it to be very successful.

Tuesday, 13 April 2010

HSPA finds success with Mobile Broadband Growth


Another GSA report titled "Mobile Broadband Growth - Reports from HSPA Operators Worldwide". As the name suggests, this contains report from different operators on their Mobile Broadband revenues growth.

Some interesting bits from the report:
  • According to a report from AdMob, smartphonedata traffic grew 193% year-over-year in the month of February 2010. Smartphonesaccounted for 48% of its traffic in February 2010, up from 35% the year before. AdMobattributed this primarily to iPhoneand Android traffic.
  • Deutsche Telekom CEO RenĂ© Obermann is expected to double revenues by 2015 with €10 billion coming from mobile data traffic. Obermann said it would double the number of 3G smartphonesin the network to around 8 million by the end of 2010
  • A recent report by In-Stat, stated that mobile broadband is now the second-largest access technology behind DSL, making up 18% subscribers
  • Telia Sonera reported that the strong demand for mobile devices, including mobile broadband and Apple iPhone™, continued. Mobile data traffic in Nordic and Baltic operations increased close to 200% while the number of mobile broadband subscriptions rose by more than 60% during 2009.
  • AT&T reported that Text messaging grew 50% YoY and picture messaging grew 130%
  • According to IDC's Worldwide Quarterly Mobile Phone Tracker, vendors shipped a total of 54.5 million units Q4 09, up 39.0% from Q4 08. Vendors shipped a total of 174.2m units in 2009, up 15.1% from the 151.4m units in 2008. Converged mobile devices accounted for 15.4% of all mobile phones shipped in 2009, up slightly from 12.7% in 2008
  • The number of people subscribing to broadband internet services in Australia grew rapidly with wireless broadband and 3G mobile services continuing strong growth in 2009, according to a new report by ACMA (Australian Communications and Media Authority). 3G now accounts for more than 50% of all mobile subscriptions, an annual increase of 44%. Internet subscriptions reached 8.4 million in June 2009, compared to 7.2 million in June 2008. Broadband subscriptions increased from 5.66 million to 6.72 million in the same period, with wireless subscribers gaining 162% to 2.1 million
  • Vodafone's Data traffic has risen 300% in the past two years. Data now represents 11% of all European service revenues. Smartphones represent 20% of handsets sales. Around 40% of the company's European 3G/HSPA networks now support 7.2 Mbps. In the coming 6 months, Vodafone plans to upgrade 20-25,000 sites across Europe to HSPA+
  • UK consultancy firm, Coda Research Consultancy, has predicted that mobile data consumption in the US is set to reach 327,000 terabytes a month by 2015, indicating a 40-fold rise in mobile data consumption over 5 years
  • Mobile data traffic from PC modems and routers is forecast to increase 4-fold between 2010 and 2014, according to a report by ABI Research. 2,000 petabytes of data will be sent and received in 2010, a figure that will rise to about 8,000 petabytesin 2014
  • Semiannual US wireless industry survey was released at CTIA in March 2010 revealing that wireless service revenues totaled $77 billion for the last half of the year. The real growth is coming from wireless data services -mobile Web, text messages, and other non-voice services. In the latter half of last year, revenue for wireless data service totaled > $22 billion, nearly a third of overall wireless services revenue and up 26% YoY. Steve Largent, President and CEO of CTIA, said in a statement. "Mobile broadband will increasingly play a vital role in people’s lives."
  • A new study by Juniper Research has forecast that more than 1 in 10 mobile subs will either have a ticket delivered to their mobile phone or buy a ticket with their phone by 2014, representing a five-fold growth over the next five years.
  • Strategy Analytics recently forecast that the number of active mobile broadband subscriptions worldwide is expected to rise to around 1.3 billion by 2014
  • ABI Research announced that shipments of mobile broadband-enabled consumer products, which includes e-book readers, mobile digital cameras, camcorders, personal media players, personal navigation devices and mobile gaming devices will increase 55-fold between 2008 and 2014 with total shipments reaching 58 million units per year in 2014

Monday, 12 April 2010

GSA report on Evolution to LTE


Global mobile Suppliers Association (GSA) published a report on "Evolution to LTE" which is available on their website here to download.

The report starts with the need for LTE and emphasises its importance with regards to the Mobile Broadband take off. It goes on to encourage the operators to embrace LTE and lists the operators that have committed to LTE roll out.

As of April 2010:
  • 64 networks in 31 countries have committed to LTE network rollout.
  • Upto 22 LTE networks would be in service end of 2010
  • 39 or more LTE networks will be in service end of 2012
Spectrum is another area of focus of this report. Along with 2.6GHz, 700MHz will probably be used in Americas, New Zealand and India. 800 MHz and 900 MHz will probably be available and used in Europe.

Finally with LTE being rolled out, it would be easy to upgrade to LTE-Advanced when the standards are finalised in Release-10.

For people interested in this report and topics, the following related presentations are available from GSA:

Wednesday, 31 March 2010

Renewed focus on TD-LTE

Last year I blogged about the 3G Americas report on TD-LTE and Motorola's gamble on TD-LTE.





The following is from daily wireless blog:

Industry momentum behind Time Division LTE continues to grow with news that a number of major operators and vendors are working with the 3GPP to allow the standard to be deployed in the USA, using the 2.6GHz spectrum band. Clearwire and its partners own the majority of that spectrum. Most of Clear’s 2.6 GHz spectrum goes unused.

Light Reading Mobile notes that China Mobile, Clearwire, Sprint Nextel, Motorola, Huawei, Nokia Siemens Networks, Alcatel-Lucent and Cisco Systems are asking for the 2.6GHz spectrum (2496MHz to 2690MHz) to be defined as a TDD band for LTE.

Outside the United States, part of the band (2570MHz to 2620MHz) is already specified for TDD. The new work will extend this compliance. The report adds that specifications for the US 2.6GHz band for TD-LTE is scheduled to be completed by March 2011.

LTE pioneers TeliaSonera, NTT DoCoMo and Verizon Wireless, will all use different frequency bands for their respective LTE networks, explains TechWorld. So for roaming in the U.S, Japan and Europe to work, modems will have to support 700MHz, 2100MHz and 2600MHz, with more bands to be used in the future. That will be a challenge for roaming, says Light Reading.


The following is from fierce broadband wireless:

The appeal of TD-LTE has widened well beyond China. The recent announcement of Qualcomm to bid for TDD spectrum in India to support a TD-LTE deployment confirms--although it was not required to validate--the emergence of TD-LTE as global technology, likely to command a substantial market share.


Why the sudden interest in TD-LTE?

There are four main factors driving a growth in support for TD-LTE:

  • The FDD LTE and TD-LTE versions of the 3GPP standard are very similar. As a result, devices can support both the FDD and TDD interfaces through a single chipset--i.e., without any additional cost. This is a hugely important new development: TD-LTE will benefit from the wide availability of FDD LTE devices that will be able to support TD-LTE as well. Unlike WiMAX, TD-LTE does not need to prove to have a substantial market share to convince vendors to develop devices. Vendors do not need to develop new devices, they simply need to add TD-LTE support to the existing ones.
  • There is a lot of TDD spectrum available, and in most cases it is cheaper and under-utilized. 3G licenses frequently have TDD allocations and upcoming 2.5 GHz auction in most cases contemplate TDD bands.
  • The increasing availability of base stations that can be cost-effectively upgraded will make it possible and relatively inexpensive for WiMAX operators to transition to TD‑LTE using the same spectrum allocation. The transition will still require substantial efforts and be justified only in some cases, but it will make it easier for WiMAX operators to have roaming deals and to have access to the same devices that LTE operators have.
  • Industry commitment to WiMAX 16m, the ITU-Advanced version of WiMAX and successor to the current WiMAX 16e, is still limited.


What's next?

In the near term very little will change. TD-LTE is still being developed and it will take time before it gets deployed beyond core markets like China and possibly a few others like China. In Europe, for instance, mobile operators will deploy LTE in the FDD spectrum and only when they will need additional capacity they are likely to move to TDD. Unlike FDD LTE, TD-LTE will move from initial deployments in developing countries, with a later introduction as a mature technology in developed countries--a quite interesting trend reversal.


WiMAX operators will also be barely affected by TD-LTE in the short term. WiMAX is years ahead in terms of technological maturity, devices and ecosystem. This gives them a strong advantage in comparison to TD-LTE operators: They know the technology already, they have a network, and they have customers. They also have the choice whether to switch to TD-LTE or not--and, more importantly, they have no pressure to do so before TD-LTE has reached the maturity they feel comfortable with or until the WiMAX 16m prospects become clearer.



Monday, 29 March 2010

Huawei's "Two Cloud" solution for Mobile Broadband


In case you are a regular and noticed my recycled image for this post then let me tell you that the post is about recycled ideas ;)

It is a well known fact that I have mentioned at various places in the blog as well that the higher the frequencies, the smaller the cell radius. Since we know that the common deployment frequencies for LTE would be around 2.6GHz then the signal penetration through walls may not be great.

As a result we will be forced to use Hierarchical cells that would allow load balancing and also higher speeds as the smaller cell sizes translate to fewer users and interference.

The following is from Huawei's website:

Based on our roadmap of early success in mobile and fixed broadband network construction, Huawei now responds to the mobile broadband dilemma facing global operators with the unique "Two Clouds" solution.

Employing optimal topologies for access networks providing DSL-level bandwidth for users across the board, the two clouds work together to deliver the most cost-effective means of enhancing user experiences.

  • A high speed cloud, consisting of Pico and AP BTSs, is typically deployed in densely-populated urban areas to deliver an average bandwidth of 2 Mb/s.
  • A continuous cloud of macro BTSs is applied for wide coverage delivering a bandwidth of 256 to 512 kb/s.

Huawei's "Two Clouds" model allows operators to profitably deploy mobile broadband networks while utilizing an intelligent site management framework to automatically adjust bandwidth and reducing construction, operation, and maintenance costs.

Incorporating this framework, flexible network mapping permits manageable, controllable mobile broadband networks, ensuring continuous network coverage in various scenarios, and provides users with inexpensive, quality broadband services. Very convincingly, Huawei's "Two Clouds" concept can reduce the cost per bit by as much as 70%.


One can guess that Self Organizing Networks would play important part in realising this in practice.

Story Source: Think Femtocell

Friday, 26 March 2010

E-UTRAN Mobility Drivers and Limitations

Many years back, when things used to be simple, I wrote a tutorial about Handovers in UMTS. It would be very difficult to write a similarly simple tutorial for LTE. Things are a bit complicated because there are many different conditions in which handovers can take place.

It was also easier to visualise the Intra-frequency and Inter-frequency handovers in UMTS and you can probably do the same to some extent in LTE but with things getting more complicated and carrier aggregation, classifying handovers in these categories may be difficult.

3GPP TS 36.300 has an informative Annex E which details the scenarios in which handovers and cell change can/will take place.

It is best to go and see Annex E in detail. Here is a bit of summary from there:

Intra-frequency mobility: intra-frequency mobility is the most fundamental, indispensable, and frequent scenario. With the frequency reuse being one in E-UTRAN, applying any driver other than the “best radio condition” to intra-frequency mobility control incur increased interference and hence degraded performance.

Inter-frequency mobility: as in UTRAN, an operator may have multiple carriers/bands for E-UTRAN working in parallel. The use of these frequency layers may be diverse. For example, some of these frequency layers may utilise the same eNB sites and antenna locations (i.e., co-located configuration), whereas some may be used to form a hierarchical cell structure (HCS), or even be used for private networks. Some frequency layers may provide MBMS services, while some may not. Moreover, E-UTRAN carriers/bands may be extended in the future to increase capacity.

Inter-RAT mobility: the aspects that need to be considered for inter-RAT are similar to those for inter-frequency. For mobility solutions to be complete with the inter-RAT drivers, relevant updates would be necessary on the legacy (UTRAN/GERAN) specifications. This will add to the limitations, which are evidently more effective in inter-RAT.


The drivers for mobility control are:

Best radio condition: The primary purpose of cell reselection, regardless of intra-frequency, inter-frequency, or inter-RAT, is to ensure that the UE camps on/connects to the best cell in terms of radio condition, e.g., path loss, received reference symbol power, or received reference symbol Es/I0. The UE should support measurements to suffice this aspect.

Camp load balancing: This is to distribute idle state UEs among the available bands/carriers/RATs, such that upon activation, the traffic loading of the bands/carriers/RATs would be balanced. At least the path loss difference between different bands should be compensated to avoid UEs concentrating to a certain frequency layer.

Traffic load balancing: This is to balance the loading of active state UEs, using redirection for example. In E-UTRAN, traffic load balancing is essential because of the shared channel nature. That is, the user throughput decreases as the number of active UEs in the cell increases, and the loading directly impacts on the user perception.

UE capability: As E-UTRAN bands/carriers may be extended in the future, UEs having different band capabilities may coexist within a network. It is also likely that roaming UEs have different band capabilities. Overlaying different RATs adds to this variety.

Hierarchical cell structures: As in UTRAN, hierarchical cell structures (HCS) may be utilised in E-UTRAN to cover for example, indoors and hot spots efficiently. It is possible that E-UTRAN is initially deployed only at hot spots, in which case this driver becomes essential for inter-RAT, not just for inter-frequency. Another use case would be to deploy a large umbrella cell to cover a vast area without having to deploy a number of regular cells, while providing capacity by the regular cells on another frequency.

Network sharing: At the edge of a shared portion of a network, it will be necessary to direct UEs belonging to different PLMNs to different target cells.

Private networks/home cells: Cells that are part of a sub-network should prioritise the camping on that sub-network. UEs that do not belong to private sub-networks should not attempt to camp or access them.

Subscription based mobility control: This mobility driver aims to limit the inter-RAT mobility for certain UEs, e.g., based on subscription or other operator policies.

Service based mobility control: An operator may have different policies in allocating frequencies to certain services. For example, the operator may concentrate VoIP UEs to a certain frequency layer or RAT (e.g., UTRAN or GERAN), if evaluations prove this effective. UEs requiring higher data rates may better be served on a frequency layer or RAT (e.g., E-UTRAN) having a larger bandwidth. The operator may also want to accommodate premium services on a certain frequency layer or RAT, that has better coverage or larger bandwidth.

MBMS: For Release-9, no new mobility procedures compared to Release-8 are included specifically for MBMS. In future releases the following should be considered. As MBMS services may be provided only in certain frequency layers, it may be beneficial/necessary to control inter-frequency/RAT mobility depending on whether the UE receives a particular MBMS service or not. For MBMS scenarios only, UE based service dependent cell reselection might be considered acceptable. This aspect also depends on the UE capability for simultaneous reception of MBMS and unicast.


While the issues mentioned above drive E-UTRAN towards “aggressive” mobility control, the limiting factors also have to be considered:

UE battery saving: The mobility solution should not consume excessive UE battery, e.g., due to measurements, measurement reporting, broadcast signalling reception, or TA update signalling.
Network signalling/processing load: The mobility solution should not cause excessive network signalling/processing load. This includes over-the-air signalling, S1/X2 signalling, and processing load at network nodes. Unnecessary handovers and cell reselections should be avoided, and PCH and broadcast signalling, as well as dedicated signallings, should be limited.

U-plane interruption and data loss: U-plane interruption and data loss caused by the mobility solution should be limited.

OAM complexity: The mobility solution should not demand excessive efforts in operating/maintaining a network. For example, when a new eNB is added or an existing eNB fails, the mobility solution should not incur excessive efforts to set up or modify the parameters.

More details available in Annex E of 3GPP TS 36.300